A narrow linewidth laser produces light with a minimal spectral width, or range of wavelengths, making it useful for various application where precise wavelength control and high spectral purity is essential.
While all lasers are inherently monochromatic, unless care is taken to stabilize the spectral output, the center frequency can vary over time, causing the time-averaged spectral linewidth to broaden. The linewidth of a laser refers to the width of the laser’s spectral line when viewed in a spectrograph. The laser linewidth is typically characterized by its full-width at half-maximum (FWHM), or its root mean square (RMS) linewidth. For example, a laser with a FWHM linewidth of 1 MHz is considered to have a narrow linewidth.
Various methods, such as grating feedback, external cavity, or active stabilization, can narrow the linewidth of a laser diode. Distributed feedback (DFB) laser diodes and external cavity laser diodes (ECLs, such as a volume Bragg grating or VBG laser diode) are common examples of narrow linewidth lasers. DFB laser diodes use a grating structure within the laser cavity to produce a narrow linewidth output. ECLs use an external cavity in conjunction with the laser diode to produce a narrow linewidth output. In the case of ECLs, the feedback for laser diode is provided by the external cavity, which is specially designed to have a high reflectivity at the wavelength of the laser diode. As a result, the laser diode is made to lase at a single frequency, which is the reflected frequency of the external cavity. This process results in a reduction of spectral width and a more stable and precise laser output.
Narrow Linewidth Laser Benefits
There are several benefits to using a narrow linewidth laser:
Precise wavelength control: They produce light with a particular and stable wavelength, which makes them useful for applications where precise wavelength control is essential.
High spectral purity: Because the spectral width of the laser output is very small, the light produced is highly pure and free from contaminating frequencies (single frequency lasers).
Improved measurement accuracy: In applications such as spectroscopy and metrology, the use of a narrow linewidth laser can improve measurement accuracy by eliminating errors that broad-spectrum light sources may introduce.
Increased signal-to-noise ratio: In telecommunications and other applications where the laser is used to transmit a signal, they can provide a higher signal-to-noise ratio compared to a laser with a broader linewidth. This can improve the overall performance of the system.
Enhanced stability: Known for their long-term stability, which makes them useful in applications where stability is essential, such as in atomic clocks.
Our Narrow Linewidth Products
We offer a selection of stabilization technologies including distributed feedback (DFB) and volume Bragg grating (VBG) diode lasers as well as a wide variety of temperature and current stabilized DPSS solutions. These lasers are available in OEM and turn-key packages which can be either single-mode or multimode beam profiles and free-space or fiber-coupled outputs. Narrow linewidth lasers are widely used in spectroscopy, gas sensing, holography, and interferometry.
How Can We Help?
With over 25 years experience providing narrow linewidth lasers to researchers and OEM integrators working in various markets and applications, and 1000s of units fielded, we have the experience to ensure you get the right product for the application. Working with RPMC ensures you are getting trusted advice from our knowledgeable and technical staff on a wide range of laser products. RPMC and our manufacturers are willing and able to provide custom solutions for your unique application.
If you have any questions, or if you would like some assistance please Contact Us here. Furthermore, you can email us at info@rpmclasers.comto talk to a knowledgeable Product Manager.
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What are Narrow Linewidth Lasers?
